Booster pump



R. R. CURTIS BOOSTER PUMP Mara; 2, 1943. 7

Filed Sept. 5, 1941 2 Sheets-:Sheet 1 J25 //a //7 n5 lPUddELL 19 GM 7/6 R. R. cuRfis 2,312,526

BOOSTER PUMP March 2, 1943.

Filed Sept. 5, 1941 2 Sheets-Sheet 2 ,Quaaa; A 0 977 I Patented Mar. 2, 1943 Russell R. Curtis, Dayton, Ohio, asslgnor to Curtis PumpOompany, Dayton,v Ohio, a corporation of Ohio Application September 5, 1941, Serial No. 409,645

' 15 Claims.

The present invention relates to a fuel system 7 and more particularly to a submergedbooster pump construction for an aircraft fuel system.

It is customary in all fuel systems of the forced feed type to provide at least one powerdriven pump to assure the proper delivery of 'fuel to an engine. In aircraft fuel systems, a plurality of such pumps are usually provided in the delivery line from .the fuel tank to the engine. The pumps are so sequentially arranged that the discharge of one pump assures adequate delivery of fuel to the suction side of the next pump.

Furthermore, this arrangement of pumps must be such as to maintain adequate delivery of fuel under a wide variety of operating conditions such as experienced in flying aircraft atvarious altitudes with the resultant changes in temperature and .pressure. Under certain conditions,less than all of the pumps may be required in operation. Consequently, each pump should be so driven that its operation is independently controlled by the pilot, One fuel pumpis therefore usually driven by the aircraft engine for delivering fuel to the engine under all normal conditions. Additional pumps are either hand driven or separately power driven at the pilot's discretion. This assures' proper fuel delivery under abnormal flying conditions at very high altitudes or during emergencies whenone or more of the other pumps partially or completely fail to operate.

In aircraft constructions, available space for accessories is very limited. v Consequently, a fuel- Generally, the present invention seeks to provide an auxiliary or booster pump of the type which separates gas from a gas-liquid fuel mixture and delivers fully liquid fuel under pressure more, the auxiliary or booster pump is so comas desired usually by av switch between the pump and a source of electricalenergy. As the entire pump construction together with the motive power is submerged in the fuel-tank, the assembly requires the provision of sealing means between the device and the liquid fuel to render the device explosion proof.

A centrifugal pump is preferably used, as it permits free liquid flow therethrough even. when not in operation. In addition,- the assembly of such a pump and a driving member therefor, such as an electric motor, requires theprovision of sealing means therebetween along the drive shaft for preventing leakage of liquids from theinlet of the pump portion to the motor portion and a barrier for preventing propagation of flame from the motor portion to the inlet ofthe lating system for the motor driving the pump whereby to scavenge vapors therefrom and to cool .the motor during its operation.

It is therefore an object of the present invention to provide a self-contained auxiliary fuel for mounting within the fuel tank.

e is to provide a driven auxiliary pump construc- 40 to the delivery line of a fuel system. Furtheractly constructed and arranged as to be mounted in a position submerged in a fuel tank. This permits space outside of the fuel tank which might otherwise be used for the pump to be available for other requirements. Likewise, such an arrangement permits the use of larger .fuel tanks A further object of the present invention is to provide a driven auxiliary pump for a'fuel system which is removably mounted within a fuel tank; c

.A still further object of the present invention tion for a fuel system which is mounted within a fuel tank-with the pump portion and its flow inlet being effectively sealed from the prime mover portion.

Another object of the present invention is to provide an air cooled vapor scavenged power driven. auxiliary pump unit for a fuel system which is small, compact, and easily mounted in a fuel tank of the system. I

A further object of the present invention is the provision of an electric motor driven booster pump unit mounted within a fuel tank for airto fill the available space either in the wings or fuselage of an aircraft as no additional space is necessary within which to mount the auxiliary or booster pump.

Motive power, separate from the aircraft engine, such as an electric motor, is provlded for driving the pump and its operation is controlled 55 Another and still further spark propagation from the electric motor to the craft fuel systems which is effectively sealed from the fuel within .the tank and against fuel leakage from the pump portion to the electric motor portion and is further sealed against ,flame or pump portion.

object of the present I as being mounted within a fuel tank 'H.

2 invention is the provision of adriven booster pump unit within the fuel; tank of an aircraft fuel system which delivers fuel free of gas .and

vapor to a delivery line fromthe fuel .tank.

The novel features believed to be characteristic of the present invention areset forth with particularity in the appended claims. The in-' an aircraftfuel-sysi'em, the deviceis adapted for use'with any vehicle in which liquid fuel is delivered-from a fuel tank to a prime mover for the vehicle..- furthermore, the pump assembly vention itself, however, both as to its organization and manner of construction, together with further objects and advantages thereof, may best be understood by reference to the following de- 1 scription taken in connection with the accom- Q'panying drawings, in which:

Figure 1 .is' a fragmentary view in vertical cross-section, with parts in elevation, of an aircraft wing and wing mounted fuel tank illustrating the manner in which the booster pump v unit of this invention is mounted within the fuel tank and the manner inwhich a tube or 'pipe extends from the unit into the slip stream of the aircraft for actuating a pump vapor-scaveng ing and cooling system;

Figure 2 is an enlarged vertical cross-sectional view with parts in elevatiomof the pump construction illustrated in" Figure 1;

Figure 3 is a fragmentary and enlarged vertical cross-sectionalview of a portion of Figure 2, with parts 'in elevation, illustrating details of construction between the pump and motor portions of the unit. of this invention; I

I0 may, if desired, be mounted within the fuel tank .H perpendicularly to the loweredge II of' the wing-construction at any point between the side 1w a11s.-i2 and I3 or may be connected. perpendicularlyj to a sidewall of the tank along a lower portion'therecf. However; the. most efficient mounting of a pump assembly'jlll'is in an upright vertical position on the lower edge I! ofthe wingconstruction as shown in order thatthe pump be positioned below the hydraulic gradient. of the fuel tank to freely'receive fuel' at. its intake. As will be more apparent'from the following description, the intake of the pump assembly" is'at the .lower end thereof -'inorder 4 that it be positioned as closely as'possible to the bottombf the fuel tank ll. Of course, when the pump assembly I0 is mounted vertically on a sidewall l2 or l3, the position introduces the 7 v undesirable-feature of maintaining "the liquid fuel above the pump throat so that the tank can never :be drained as completely as when the pump'is positioned upright, on the bottom wall ofthe fuel tank. l a y The pump and prime mover assembly is best Figure 4 is a fragmentary and enlarged vertical cross-sectional view of a portion of a pump illustrated in Figure 2, with parts in elevation.

as seen when taken in the plane indicated by the line IX-IX of Figure 5;

Figure 5 is a transverse cross-sectional view, with partsin elevation, of a pump construction as seen when viewed in a plane taken substantially along the line -VV of Figure 2; and,

-Figure- 6 is a vertical cross-sectional view,

I with parts in elevation, along a portion of the motor assembly illustrating the manner in which the motor housing is attached to the pump casing.

including a prime mover thereforfis illustrated In the present construction, the sidewalls of the As best seen in Figure 1, a-pump assembly 10,

illustrated in 2 and includes apump porvolutechamber 26 communicating along the in-- ner periphery thereof with a throat inlet .21 and opening in the ,outer periphery thereof into a dischargemember 28 which,iin turn, as shown in Fig. 1, is connected to a fuel delivery line I v The throat inlet -21"in c'ludes an inwardly tapered surface 30 and a substantially cylindrical surface 3|. The surface 3| and the ind tion i011 and a prime mover'portion-Jtb. The

" ternal volute' chamber 25 are connected by-a fuel tank II are formed by front and rear wing spar webs 12 and I3 which are connected tothe upper surface or top wing skin [4 and the lower surface or bottomwing skin l5 of an aircraft wing construction ,IG-by means of' front and rear wing spars I1, l8, [-9, and". As shown; the spar webs l2 and I3 are connected to. the

vertical flanges of the wingspars by means of rivets. The top and bottom wing skins are also connected to the horizontal flanges of the wing spars by means of rivets. The ends of the fuel tank are formed by transverse wing ribs (not shown). Figure 1, the tank II is provided with a vent tion.

It is to be-understood, however, that the tankllrmay be'a self-contained unit of such con- In this construction as illustrated in 2| in the upper surface 14 of the wing construc- I figuration as to be inserted within the ;wing i construction and supported therein by saddles and strapped in place to' permit some degree of freedom to avoid the tank being subjected to undue strain as the wing strucure deflects under load.

.It is to be further-understood, of'course, that although the pump assembly III of the present invention is illustrated as, forminga portion of v, y be hereinafter described.

flat. surface 32., An opening 33 connects. the

outer faceof the head 23 with the internal 7 volute chamberlfi and receives therein a cap member 34 removably connected .to the head 23 by studs (not shown) or other suitable means.

The cap member 34 is cup-shaped 'and has an annular' flange 34d extending outwardly from the periphery thereof for engagement against the outer surface of the head 23 and may besuitably: apertured to receive therethrough the connecting means such as the studs.

25 opposite the discharge member 28 and terminates at its 'upper'enii in. a.cylindrical casing portion 36. A wall 31 of the'casing' slopes inwardly from the casing portion 38 toward the axisjof the pump assembly and thence down wardly as illustrated in Figure 2 where ittermlnates in a cylindrical shaft housing 38., It is to be noted that the shaft housing Blis in 1 axial alignment with the-throat inlet 21. v

. The outer periphery of the casing portion 3| is externally threaded as at 39 for a purpose to The motor casing 22 includes a cylindrical member 40 having reduced end portions defining An integralcolumn 35 extends angularly -up-" wardly from the-side of the thickened portion shoulders and 42. The member 40 is inserted into the pump casing portion 36 with its shoulder 4| abutting against the end-thereof, An apertured end cap 43 embraces the opposite end of the cylindrical member 48 and abuts against the shoulder 42 thereof.

vAs shown in Figure 6, the sloping casing wall 31 is provided with internally threaded circumferentially spaced bosses such as 44, whilethe end cap member 43 has circumferentially spaced apertures for receiving therethrough a plurality of draw bolts 45, only one of which is shown.

'Each draw bolt 45 has a head 45a for abutment shaped enclosure member 41, formed preferably of thin sheet metal, has its end margin 48 flared outwardly to embrace the packing 46. A tubularv a pump assembly through the'bores 59 and 68 into theinside of the motor portion of the pump I assembly. v

The electric motor a shaft 63 and is supported in the housing 52 by means, of an anti-friction bearing 64. The

shaft 63 is also supported in the shaft housing 36 by an anti-friction bearing 65. A lug 66m 1 the bearing against rotation.- The slot 61 also the bearing 65'seats within a slot 61 in the end of a shaft housing 38 to hold the outer race of providesan airflow passageway from the motor casing into the shaft housing.-

The details of construction along the pump shaft 63 below the anti-friction bearing 65 are best illustrated in Fig. 3. The shaft housing 38 has an inwardly extending shoulder 68 intermediate the ends on the inner periphery thereof. This shoulder divides the inside of a shaft housing 38 into connected chambers 69 and 18. It

. will be noted that the chamber 69' has a larger sleeve member 49 has an intermediate shoulder 58 formed on the inner periphery thereof and internal threads 5| at one end thereof. The tubular sleeve member 49 embraces the free end of the cup-shaped enclosure member 41 andthe internal threads 5| thereof are threaded on the external threads 39 of the casing portion 36. The tubular member.49 is threaded on-the casing portion 36 until the internal shoulder 58 thereof tightly abuts against the outwardly flared portion 48 to hold the latter in sealing engagementwith the packing 46. This provides a fluid seal between the casing portion 36 and the enclosure member 41.

A bearing housing 52 is suitably carried in spaced relation from the end cap member'43 by any suitable means such as webs from the cap (not shown) so that the'axis of the housing is in alignment with the axis of the shaft housing 38.

. The prime mover is preferably an electric motor comprising an armature .53. axially spaced field coils 54 and 55, a commutator 56 and commutator-brushes such as 51, only one of which is shown. The commutator brushes have connected thereto a conductor. 53 which extends through the hollow supporting column 36 in a manner now to beidescribed.

The supporting column 35 is hollow through.- out its length and includes a bore 58 partially therethrough for loosely receiving the conductor 58 and an enlarged bore 68 at its upper end for loosely receiving therein a sleeve member 6|. The sleeve member 6| is tubular and has a reduced bored portion for tightly receiving .therethrough the conductor 58. The outer diameter. of the sleeve 6| is approximately .010. inch smaller than the inner diameter of the enlarged bore 68 to provide an air space therebetween. The 'upper end of the sleevev 6| has' 6| and the inner periphery of the bore 68 as air flow space is provided from the outside of inside diameter than the chamber 18. i

A flame barrier construction 1|, within the chamber 63, includes a sleeve member 12 having its outer peripher'y press flttedinto the upper enlarged end of a chamber 69 to seat againstthe shoulder 13.

The inner portion of the member 12 is formed as a tubular sleeve 14 and is sized for receiving the shaft 63 therethrough in spaced relation. A second member 15.is cupshaped and has one end 16 thereof internally bored fo'r'snugly engaging a portion of a shaft 63 in spaced relation from the sleeve 14 of the first member. The upper portion of the member 15 is cup-shaped to provide a cylindrical sleeve portion 11 overlappingfthe sleeve portion 14 in spaced relation therefrom. As the shaft 63 rotates, the member 15 rotates therewith and the tortuous path between the members and between the sleeve portion 18 and the shaft 63 assures that flame from an explosion within the electric driving motor willnot be propagated beyond the chamber 88. It is well known that flame will not 'pass'through tortuous paths of reduced size, and since the pump assembly i8 is to be submerged in the fuel of the fuel tank, it is necessary that the driving motor portion be .sealed from the pumping portion of the assemblyin order that'the latter be made explosion proof. Furthermore, as the pump assembly of this invention is intended preferably for use on aircraft, it is desirable to hold the weight and size to a minimum, and consequently the labyrinth .ar-

rangement defining the tortuous path of the' flame barrier construction 1| is provided for obliquid leakage therebetween by a seal construction 18. This seal construction comprises a metal ring 19 loosely embracing a reduced portion 630 of the pump shaft and seated on the inwardly extending shoulder 68 formed on the inner periphery of the shaft housing 38 intermediateits ends. The marginal edge at the periphery of the ring member 19 is of reduced thickness to define an annular slot 38 between the body of the ring and the inner periphery of the chamber 18. A resilient ring member 8| is seated in the slot 88 and is engaged by a tubular seal nut 62. It is to be noted that the tubular seal nut 82 is externally threaded as at 83 for engaging internal threads 84in the'pump housing defined by the chamber 18. When the seal armature 53 is carried by nut 82 is threaded toward the shoulder so, the resilient ring member 9| is expanded in a radial direction to tightly seal the slot 99.-

- A compressed graphitic carbon. seal ring" 95 Y closely embraces the shaft portion 990 but is not necessarily driven thereby. The carbon ring 95 and the metal seal ring 19 are mounted in sliding face engagement. A resilient cushion washer 99, preferably formed of fuel and oil resisting Y artificial'rubber, such as Neoprene, abuts against 19 the carbon ring 95. The cushion washer-snugly engages the shaft portion 99a in sealing relation therewith. A cup member QTSUIIOlHldSjthG shaft portion 93a, the resilient cushion washer 99 and'the carbon ring 95. Axially extending tangs or fingers 99 engage within suitable slots in a sleeve coupling member 99. The opposite end of the sleeve coupling member 99 has axially extending tangs or fingers 99 for a purpose to be later described.

. 2 The free end of the pump shaft 99 is'further reduced in a portion 99b for the purpose of receiving thereon the centrifugal pumping mechanism now to be described. The pump portion l9a of the pump assembly'has an impeller 9| com- 5 prising a hub 92, a flat disk flange 99,.and a series of radially curved vanes 99, as shown in Figure 5. The impeller is secured to the shaft portion 93b by a key 95, a washer 99, and a nut 91 threaded on-the end of the shaft portion 99b.

The key 95 is L-shaped and has one leg 98 longer thanthe opposite leg 99. The shaftportion 99b is provided with a longitudinally extending partially circular keyway I99, such as used with Wogodrufi keys, in registry with a radially extending segmental circular keyway in the outer face of the impeller flange 99. The key leg 99 is curved to complementally seat within the keyway I 9|, while the key leg 99 is curved to seat within a portion of the curved keyway I99. It is to be 4 noted that when the key 95 'is seated within the keyways I99 and IM the leg 99 extends upwardly beyond the outer surface of the impeller flange 99. This extending portion of the key leg 99 is seated in the shaft keyway I99 and extends into d5 an aperture (not shown) of the washer 99. When the nut 91 is threaded to the externally threaded portion I92 of the shaft portion 9917, the washer 99 surrounds the shaft and the. key leg 99 and seats against the key leg 99 to tightly maintain the vkey within the keyways whereby the impeller is locked to the shaft.

The circularly cut keyway I9I in the flange 99 is conveniently cut with a milling cutter and the leg 99 of the key by being seated in thewasher 55 99 is held against radial displacement out of the thus cut slot. The key is so shaped as to readily permit its entry after the impeller has been assembled on the shaft. 'I'his'is eflected' by rocking the key into the aligned keyways to thegjb position shown and then tightening the nut against the washer as previously described.. The heretofore required press fitting of a rectangular Woodruff key in a slot formed longitudinally in the shaft portion 99b before mounting the im- 99 pelleron the shaft is thus avoided.

The free end of the impeller-hub. 92 is provided 7 with axially extending slots for receiving therein the tangs 99 on the coupling sleeve-99. A coil spring I99 embraces the coupling sleeve 99 and 79 the impeller hub'92 and is seated atone, end against the impeller flange 99 and atitslot er end against the cup member 91'. The coil sprl sexerts a constant force on the resilient cushion washer 99 for maintaining the carbon 11118:" 19

tightly against the metal seal ring 'I9."At the same time, the urging of the cup by the spring serves to squeeze the resilient cushion washer 99 in the cup member 91 to insure rotation of the washer 99 with the cup and the washer 99 in turn drives the carbon ring to effect sliding face engagement with the metal ring 19. This construction provides a seal between the chambers 99 and I9. v It is preferred that graphitic carbon be used in the rotating seal ring 95 as it provides satisfactory wear and seal characteristics during the 9 pressure sliding engagement with the face of the metal seal ring I9. It is to be understood, however, that any other suitable material having similar'properties may be used.

The frictionaldrive for the rotating carbon seal ring 95 has been found necessary due to the fragility of the material as it will chip or crack 0 if forced on the shaft in order to be driven directly thereby..

As shown in Figure 2, the shaft housing 99 is in axial alignment with the throat inlet 21. The

pump impeller 9I is inserted through the opening 33 and is connected to the shaft portion'99b in a manner as previously described. When so connected, the upper edges of the curved vanes 99 lie adjacent the flat surface. on the under side of the throat. The cap member 99 is then inserted into the opening 99 to close the same and is connected to the flange 29 in a manner as previously described herein. It will be noted in Figure 2 that the cap member 99 extends into closely spaced relation from the outer surface of the impeller flange 99'. The space between the end of the cap 99 and the flat surface '92 on the underside of the throat forms a pumping chamber for the impeller'vanes adjacent the internal and extends from the chamber 99 to the outer face of the head 29. The outer end of the opening I95 is enlarged and internally threaded as at I99 for receiving therein a coupling member I91. A tube I99 is carried by the coupling I91 and extends away from the head 29 in substantially right angular relation thereto for a purpose to be later described.

In Figure 1, there is illustrated the construc- I tion by which the pump assembly I9 is removably connected to and withinthe fuel'tank II. The

lower edge II of the wing construction is upwarde .ely offset to providea circular ring portion 199..

The lower wing edge I5 is addltionaly offset to form an adjacent ring supporting portion 9.;

The latter ring supporting portion is internally apertured to snugly receive therein the ovalshaped head 29. I

A hanger-bracket III has one end II2 con nected to the side wall I9 of the fuel tankby' rivets, as shown in Figure 1, or by other suitable means. The bracket is oifset downwardly and is provided-with a forwardly extending portion II9 which is suitably apertured as at II9 for receiving therethrough the entire pump assembly I9- above the .head 29. The aperture 9 is smallerjhanthe oval-shaped flanged periphery of the head 29 so that the latter abuts against the hanger end III and is connected thereto by means of bolts or the like, which extend through the head apertures 26. The hanger portion II3 of the bracket III is connected to the ring support portion I III by means of bolts I I6 or the like. In the .present instance, it is preferred that the connecting members H5 and H6 be cap screws in order that the pump assembly l6 may be easily assembled to and disassembled from the fuel tank II from the outside thereof.

If desired, a gasket (not shown) may be inserted between "the hanger bracket portion H3 and the pump head 23 to insure against liquid leakage therethrough.

It will be. noted that, when the pump assembly is so mounted within the fuel tank II, the tube I06 extends downwardly below the lower edge I! of the wing structures. A flat closure plate I" is connected to the ring supporting portion I09 by the cap screws H8 and the outer surface thereof'is flush with the outer surface of the lower wing edge I5. .The closure plate In closes the depression formed by the offset por-' tions of the wing edge I5 to provide a mounting for the pump assembly and thereby forms a smooth continuation of the wing surface.

for receiving therethrough the tube I08.

The flow of air in the slip stream past the end An, opening 9 is formed in theclosure plate HT of the tube I08 creates a partial vacuum in the tube and induces a flow of air through the interior of the motor as illustrated by the solid line arrows in Figure 1. As previously described with Figure 2, the air inlet is through the bore 58 where it passes through. the space between the bore 60 and the sleeve 6|, through the opening 63. around the interior of the motor portion IIIb, through the slot 6'! in the end ofthe shaft housing 38, through the flame barrier construc- 1 tion 'II and then downwardly through the open- 1118 I05 and the tube I08.

The flow of air through the motor effects a side wall I3 and through a tube or other covering I20. The end of the conductor 58 is connected to a source of electrical energy (not shown).

The discharge member 28 is connected to one end of a fuel delivery line 29v by means of a clamp I2I. The other end of the fuel delivery line 29 is connected by a clamp I22 to a deliverv line I23 which extends through the fuel tank side wall I3. The fuel delivery line I23 extends to the carburetor of the vehicle engine (not shown).

If desired, the fuel delivery line 29 may be formed of flexible material impervious to the liquid fuel I24 such as gasoline.

When the motor portion I Ilb is energized at' the discretion of the. pilot, the curved impeller vanes, agitate the liquid fuel such as gasoline flowing through the inlet throat 21. The liquid fuel may contain occluded gases, loosely dissolved gases and volatiles about to be liberated the liquid in the form of bubbles I26 which rise through the liquid and burst at the surface of booster pumps pressure the bubble freed liquid above the vapor pressure of the liquid to permit additional'vaporization. The pressured liquid is held under pressure throughout the fuel delive line.

When the fuel enters into the inlet throat 21, the inner tapered portions I26 of the curved vanes 94 agitate the fuel and beat out, in bubble form, the gases, vapors and loosely dissolvedvolatiles. The curved vanes form an upwardly and outwardly spiraling whirlpool path in the fuel and the liberated gas and vapor bubbles I25 follow the whirlpool path as shown in Figure 1. As soon as the bubbles reach the surface of the liquid they burst into the atmosphere. The bubble freed fuel is centrifugally forced through the pumping channels defined by adjacent vane portions I21, the flat surface 32 and the'impelier flange 93' into the volute chamber 26 and the de I livery line 29. 7

The speed at which the gas and vapor bubbles I25 are liberated and the pressure at which the fully liquid fuel is pumped =may be varied by varying the speed at which the pump impeller is driven.

If it is desired to strain the liquid fuel as it is drawn into the pump inlet 21, a screen I28 may be mounted as illustrated .in Figure 1. The size of mesh used will depend on the amount of filtering desired but it must be large encugh so that the bubbles I25 will be forced therethrough by the agitating vane portions I26 of the revolving impeller. The screen I23 will be generally cylindrical in shape with its upper end abutting against the tubular sleeve member 49 and its lower end being seated on the head 23. Portions are cut out in order that the screen may snugly fit against projecting portions such as the discharge member 28 in a manner as shown in Figure 1.

It will be apparent from the foregoing that'I have provided a driven pump assembly adapted for mounting in a tank to be submerged in liquid within the tank and having pump and motor portions effectively sealed against the leakage of liquid fuel or fuel vapors therebetween. The motor and pump devices of this invention are explosion proof, vapor scavenged, and air-cooled.

While a particular embodiment only of this I invention has been illustrated, it will, of course,

be understood that the inventionshould not be limited thereto, since many modifications may be made, and, therefore, it is contemplated by the appended claims to cover all such modifications as fall within the true spirit and scope of the present invention.

I claim as my invention:

1. In a liquid fuel system including a fuel tank, the improvement which comprises a fuel pump mounted in said tank'for receiving fuel directly therefrom, and means associated with said pump for beating out bubbles of gas and vapor from the liquid fuel, said means including agitators positioned for continuous open communication with fuel in the tank to act on the fuel before it becomes confined in the pump.

2. In a fuel system including a fuel tank and a. pump and motor unit submerged in the fuel in said tank, the improvement comprising a casing for said unit forsealing the motor portion of the unit from the fuel in the tank, means removably mounting said casing in said tank, and

passageways through said casing connecting the interior of the casing sealing the motor portion of the unit with the exterior of said tank for fluid circulation around said motor portion.

3. In a fuel system including a fuel tank and a pump and motor unit submerged in the fuel in said tank, the improvements comprising a casing having connected portions separately housing the pump and motor of said unit, means mounting said casing in said fuel tank, and other means defining inlet and outlet fluid flow paths extending through the casing portions housing both the pump and motor of said unit for connecting the interior of the casing portion housing said motor with the exterior of said .tank for fluid circulation therebetween.

exterior of said tank for fluid flow therebetween,

4. In a fuel system including a fuel tank and a pump and motor unit submerged in the fuel in said tank, the improvement comprising a casing adjacent their peripheries, means removably mounting said casing in said tank, and passage- 'ways through said casing portion for the pump and through said support portions'for connecting the interior of the casing portion for the motor with the exterior of said tank for fluid circulation therethrough.

5. In a fuel system for a-vehicle including a fuel tank and a pump and motor unit submerged in the fuel in said tank, the improvements comprising a support casing having an inlet opening for mounting the pump of said unit in said tank, driving means for said pump, a casing sealing said driving means from the interior of said tank, and support means connecting said casings, said support casing and support means having passagewaystherethrough communicating with the interior-of said driving means casing, and a vent member extending from the exterior of said ve-.

hicle into communication with one of said pasing.

6. In a fuel system for a vehicle including a mounting flange, a bracket carried by said tank 1' I fluid circulation is effected through said passageways and the interior of said driving means casfuel tank and a pump and motor unit submerged in the fuel in said tank, the improvements comprising a flanged base, means connecting saidmeans and casing portions having passageways therethrough connecting the interior of said motor casing portion with the exterior of said tank for fluid flow therebetween, and a suction pipe extending from one of said passageways to the atmosphere for drawing air through the other of said passageways and the motor casing portion.

- 7. In a fuel system for a vehicle including a an electrical conductor extending through one of said passageways connecting saidmotor with a. In a fuel system including a m1 tankand a pump and motor unit submerged inthe fuel tank, the improvements comprising a casing for said pump and motor unit having a mounting flange thereon, and an internal mountingin said tank for said pump and motor unit, said internal 1 mounting having aflange on a portion of a wall of said tank with an opening for receiving the mounting flange of said pump and motor unit therein, a mounting bracket carried by a wall of said tank and having an aperture for receiving a the casing for said pump and motor unit therethrough, and meansconnecting said flangesto" v said bracket-for sealing said encased pump and motor unit in said tank. a

9. In a fuel system including a fuel tank and a pump and motor unit submerged in the fuel tank, the improvements comprising a casing for said. pump and motor unit having, amounting flange thereon, and a removable mounting for said encased pump and motor unit in said tank, said removable mounting having a flange .inturned from one wall of said tank with an aperture therein for complementallyreceiving said having an aperture therein for receiving 'said encased pump and motor unit therethrough and overlapping said mounting flange thereon, means I turned flange of the tank and being flush with said one wall of the tank.

10. In a fuel system including a tank for a pond of liquid fuel and a fuel pump and motor .unit in said tank adapted to receive liquid from under pressure, the'improvements of a support I construction for sealing the motor of-s'aid unit from the pond of fuel in said tank, and means including an inlet and an outlet deflningan .air flow path through said support construction for circulation of air from'andto the outside of the tank through the interior of the support construction around the sealed motor of the unit to cool the motor.

11. A fuel pump assembly comprising a hollow casing having connected bores of unequal size,

an impeller in said casing, 'the smaller of said bores being in a portion of the casing overlapping the impeller and the larger of said bores surrounding the periphery of said impeller, and a removable closure in said larger bore whereby said impeller is removable from said casing.

12. In a fuel system, a tank having an apertured wall portion at br near the bottom thereof, a, pump and motor unit in said tank, said unit having spacedconnected pump and motor portions with a pump inlet throat between the porfuel tank and a pump and electrical'motor unit submerged in the fuel insaid tank, the improvements comprising a casing having spaced portions connected'by support portions, said casing portions respectively housing themotor and pump of said'unit, said casing and support portions having passageways therethrough connecting the interior of said motor casingportion with the tions in open communication with the interior;

; within the tank.

13; A pump and motor unit adapted for mounting in a tank on an apertured wall portion thereoi which comprisessaid having longitudinally spaced connected pump and motor portions with a pump inlet lying in the space between the portions, an apertured head on the end oi said pump portion remote from the motor portion adapted to be seated in the aperture or I the tank wall, and a closure for the head aperture adapted to be'removed from outside 01 the tank to give access to the interior of the pump. 14. A pumpand motorassembly adapted for submersion inliquids to deliver gas-freed liqand vapor from liquids in which the assembly is mounted before the liquids become confined in the pump chamber.

15. In combination witha container having an aperture in a wallthereof, a 'casing' mounted in said container around the aperture-thereof, said casing defining a motor chamber and an openended pump chamber in spaced relation from the uids which comprises a casing having spaced opposedv pump chamber and motor chamber portions, said pump chamber portion having a. cenitons, a pump impeller in the pump chamber portion connected to said drive means, and agitators associated with said impeller positioned for open communication with the space between motor" chamber, one open end of the pump chamber opening toward the motor chamber to Join the space between the motor and pump chambers with the pump chamber, the other open end of the pump chamber being aligned with the container aperture; a motor in the motor chamber having a drive shaft extending across the space between the chambers, an. impeller in the pump chamber driven by said shaft, and a removable cap accessible fromoutside the container closin: said other open end-oi the pump'chamber.

" RUSSELL R, CURTIS.-

, 7 [the casing portions to. beat out-bubbles of gas 

